JP2010175576A - Image forming apparatus, method for controlling image forming apparatus, and program for controlling image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that appropriately detects the position of a developing rack. <P>SOLUTION: Each of color developing units mounted on the developing rack is provided with a memory substrate. A contact for carrying out communication by connecting to the contact of the memory substrate is set in the body of the image forming apparatus. A period during which the communication output of the contact of the memory substrate is at a High level is detected by a CPU. By correlating the output of a developing rack motor drive pulse and the period, the position of the middle of the High level period is determined as a home position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program. The present invention relates to an image forming apparatus including the image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program.

  An electrophotographic image forming apparatus (MFP (Multi Function Peripheral), facsimile apparatus, copier, printer, etc.) having a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function, The charged photoreceptor is exposed to form an electrostatic latent image.

  In an image forming apparatus, a plurality of developing devices (so-called toner cartridges) each storing color toners used for color printing are arranged around a rotation axis of a rotary (developer holding rack) and rotated to develop them. In some cases, a toner image is formed on a photosensitive member by sequentially switching the developing device to a developing position. A full-color image is formed by a so-called four-cycle method.

  It is possible to manage the remaining amount of consumables by mounting a memory substrate for managing consumables data on a developing device mounted on the image forming apparatus. The rotary is rotated to stop the communication contact formed on the memory substrate of the developing device at a predetermined communication position. At the communication position, the contact formed by the leaf spring of the machine body and the contact of the memory board are electrically connected. As a result, the CPU for controlling the machine body and the memory substrate can communicate with each other.

  In the four-cycle image forming apparatus, the home position of the developing device holding rack is detected. In order to detect the home position of the developing device holding rack, a slit is provided in the circumferential direction of the end portion of the developing device holding rack. This slit is detected by a photo sensor.

  Patent Document 1 below discloses a structure in which a communication unit is arranged in a developing device installed in a developing rack of a 4-cycle machine, and an antenna unit is arranged on the image forming apparatus main body side. When a communication error occurs at the communication position, the position of the antenna unit is corrected. Japanese Patent Application Laid-Open No. H10-228688 describes detection of the home position of the developing rack. Detection is performed by providing a position detection plate on the rack and a detection sensor on the image forming apparatus main body side.

JP 2008-139637 A

  FIG. 13 is a schematic cross-sectional view showing the overall configuration of a four-cycle digital full-color printer (hereinafter simply referred to as “printer”) employing an intermediate transfer method. The overall configuration of the printer and the configuration of its control unit will be described below.

  (1) Overall printer configuration

  As shown in FIG. 13, the printer 1 includes a photosensitive drum 2, a developing device 4, an intermediate transfer belt 6, a cleaner 8 for cleaning residual toner on the intermediate transfer belt 6, a fixing device 9, an exposure unit 11, and the like. And a paper feed unit 20 having a paper feed cassette 21 for containing the recording sheet S, and the like, and is a digital printer that forms a full-color image by a known electrophotographic method.

  The printer 1 is connected to an external computer or the like (not shown) via a network such as a LAN (Local Area Network). When the control unit 100 receives print data of a color image from the external computer, the control unit 100 adds necessary processing to the yellow (Y), magenta (M), cyan (C), and black (K). ) Image data of the developed color is generated.

  These development color image data are converted into a semiconductor laser drive signal of the exposure unit 11 and output to the semiconductor laser. As a result, a laser beam (indicated by a broken line in FIG. 13) is emitted from the exposure unit 11 toward the photosensitive drum 2.

  The surface of the photosensitive drum 2 which is cleaned by the cleaning blade 5 and is uniformly charged by the charging charger 3 and rotates in the “A1” direction in the drawing is irradiated with the laser beam in the main scanning direction (the transport direction of the recording sheet S). The image is output so as to be exposed and scanned in a direction perpendicular to the plane of FIG. As a result, an electrostatic latent image of the corresponding development color is formed on the photosensitive drum 2.

  The developing device 4 includes four developing units 40Y to 40K (an example of consumables) containing a developer containing toner of each color of Y, M, C, and K. The developing unit 15 has 90 degrees in the circumferential direction. They are installed at regular intervals. The developing rack 15 can be rotated in the direction of the arrow “B” in FIG. 13 about the axis of the support shaft 16. The developing device 4 is rotationally driven by a developing rack motor (not shown). The control unit 100 performs development so that the home position of the developing rack 15 is detected and the developing rollers 41Y to 41K of the developing units 40Y to 40K corresponding to the next developing color are located at the developing position facing the photosensitive drum 2. The rack 15 is controlled to rotate. As a result, the electrostatic latent image on the photosensitive drum 2 is developed.

  The intermediate transfer belt 6 is endless and is stretched by a primary transfer roller 61, a drive roller 62, and a driven roller 63. The intermediate transfer belt 6 travels in the direction of the arrow “E” by the rotational driving force of the driving roller 62. Here, while the primary transfer is performed by the primary transfer roller 61, a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roller 61. The drive roller 62 is grounded.

  The toner image formed on the photosensitive drum 2 is transferred onto the intermediate transfer belt 6 by the electric field generated between the primary transfer roller 61 and the photosensitive drum 2 at the primary transfer position “D” (1 Next transfer). At that time, the image forming operation on the photosensitive drum 2 is executed at a timing at which the toner images of the respective colors are transferred to the same position on the intermediate transfer belt 6 in the order of Y, M, C, and K. As a result, the toner images of the respective colors are sequentially superimposed on the intermediate transfer belt 6 to form a full color toner image.

  The secondary transfer unit 7 includes a secondary transfer roller 71, a holding member 72 that rotatably supports the secondary transfer roller 71, and a transfer solenoid 73 that moves the holding member in the left-right direction in the drawing.

  When a full-color toner image is formed on the intermediate transfer belt 6 as described above, the secondary transfer roller 71 is pressed in the direction of the drive roller 62 to charge the secondary transfer roller 71 with a charge opposite in polarity to the toner charging polarity. Apply. At the secondary transfer position “F”, a full-color toner image is formed on the recording sheet S fed from the paper feed cassette 21 by an electric field generated between the secondary transfer roller 71 and the driving roller 62 facing the secondary transfer roller 71. Is secondarily transferred.

  The recording sheet S accommodated in the paper feed cassette 21 is fed to the timing roller 23 by the rotation of the paper feed roller 22. The recording sheet S is sent to the transfer position “F” by the timing roller 23 in synchronism with the operation of forming a full-color toner image on the intermediate transfer belt 6.

  The recording sheet S to which the full color toner image is transferred is conveyed to the fixing device 9 where it is heat-pressed. As a result, the toner on the surface of the recording sheet S is melt-fixed, and then the sheet is discharged to the discharge tray 13 by the discharge roller 12.

  The cleaner 8 as a cleaning member of the intermediate transfer belt 6 is obtained by pivotally supporting a holding member 83 that holds a cleaning blade 81 at the tip so as to be swingable by a support shaft 82. By moving the lower end of the holding member 83 in the left-right direction in the figure by the cleaner solenoid 84, the pressing / separating operation of the cleaning blade 81 against the surface of the intermediate transfer belt 6 can be executed.

  In each of the developing units 40Y to 40K, memory boards 42Y to 42K on which information such as color information of each developing unit, an LOT number, and the number of printed sheets are recorded are mounted.

  A photo sensor 17 for detecting the development rack home position is arranged on the circumference of the development rack 15.

  (2) Configuration of control unit 100

  FIG. 14 is a block diagram illustrating a configuration of a control unit included in the printer of FIG.

  As shown in the figure, the control unit 100 includes a CPU 101, an interface (I / F) unit 102, an image processing unit 103, an image memory 104, an LD driving unit 105, a ROM 106, and a RAM 107.

  The ROM 106 stores a program that can be executed by the CPU 101 for driving the developing rack.

  The I / F unit 102 is a communication interface (LAN card, LAN board, etc.) for connecting to a LAN.

  The image processing unit 103 adds a known color correction process or the like to the image data from the external device received via the I / F unit 102, and generates YMCK image data as a development color. The generated image data of each color is temporarily stored in the image memory 104, and then read out by the CPU 101 and transmitted to the LD driving unit 105 when image formation is executed.

  The LD driving unit 105 has a line memory inside. The LD driving unit 105 sequentially holds the image data for each scanning line. The LD drive unit 105 converts it into a drive pulse for driving the semiconductor laser of the exposure unit 11 and then sends it to the exposure unit 11.

  As a result, exposure scanning of the photosensitive drum 2 based on the image data is performed, and electrostatic latent images of each development color are sequentially formed on the photosensitive drum 2.

  The CPU 101 reads a necessary program from the ROM 106, operates the photosensitive drum 2, the intermediate transfer belt 6, the secondary transfer unit 7, and the cleaner 8 of the image forming unit 10, and the transfer roller solenoid 73 and the cleaner solenoid. 84 and the operation of the developing rack motor 91 are controlled. The CPU 101 communicates with the memory boards 42Y to 42K mounted on the developing device. The CPU 101 inputs a signal from a cover opening / closing sensor 99 that detects opening / closing of the cover of the apparatus main body.

  The CPU 101 controls the operation of the paper supply roller 22 of the paper supply unit 20 in an integrated manner to smoothly execute an image forming operation and the like. The CPU 101 also has a timer function, a counter function, etc., and uses them when the control program is executed.

  Further, the CPU 101 executes data acquisition processing related to fluctuations in the traveling speed of the intermediate transfer belt 6 accompanying the contact / separation operation of the transfer roller 71 and the cleaning blade 81, and correction control associated therewith.

  The ROM 106 stores various programs for image forming operation, color misregistration correction control, and reading and writing of memories on the development unit mounting memory boards 42Y to 42K.

  The CPU 101 controls the developing rack motor 91 to move the developing rollers 41Y to 41K of the respective color developing units 40Y to 40K to a predetermined position facing the photosensitive drum 2 at the time of developing each color, or to each developing unit mounted memory substrate 42Y to 42Y. The contacts (contacts A to C) of the development unit mounted memory boards 42Y to 42K are connected to the main contacts 52 (main contacts 52a to 52c) of the memory board connection contact unit 50 for reading and writing the memory of 42K. Then, the developing rack 15 is moved to a predetermined position.

  The CPU 101 inputs a signal from a photo sensor (home position sensor) 17 for detecting the development rack home position arranged on the circumference of the development rack 15.

  FIG. 15 is a diagram showing a detection mechanism of the photosensor 17 for detecting the developing rack home position.

  A home position detection cutout 18 is formed on the circumference of the side of the developing rack 15. The development rack home position detection photo sensor 17 detects the position of the home position detection cutout 18 that moves as the development rack 15 rotates. By detecting the presence or absence of this notch, the home position of the developing rack is detected.

  FIG. 16 is a diagram showing an output waveform of the home position sensor 17 having the configuration of FIG. 15 and a drive pulse waveform of a motor for driving the developing rack.

  The developing rack motor 91 is a stepping motor and is driven by a developing rack motor driving pulse shown in the figure. The developing rack 15 in this example is configured to rotate once with a stepping motor driving pulse number of 2,000 pulses.

  When the developing rack 15 rotates and the notch 18 for detecting the home position on the side circumference of the developing rack 15 shown in FIG. 15 reaches the position of the home position sensor 17, the light emitting element in the home position sensor 17 The light is not reflected by the cutout. As a result, the home position sensor 17 cannot detect the reflected light by the light receiving element. As a result, the sensor output waveform changes from the high level to the low level.

  When the sensor passes through the position of the notch 18 for detecting the home position, the reflected light enters the light receiving element, so that the sensor output changes from the low level to the high level. The main body control CPU 101 detects a period during which the output of the home position sensor 17 is at the low level. By correlating the output of the developing rack motor drive pulse with the above period, the center position of the Low level period is determined as the home position.

  As shown in FIG. 16, the number of developing rack motor drive pulses in the low level period of the output of the home position sensor 17 is nine. Therefore, when the output of the home position sensor 17 is switched from the Low level to the High level, a place where five pulses that are half of the Low level period are returned is determined as the home position.

  As described above, in the four-cycle image forming apparatus, it is necessary to provide a dedicated home position sensor for detecting the position related to the rotation of the developing rack. This has led to an increase in cost, which has hindered the downsizing of the machine.

  The present invention has been made to solve such a problem, and provides an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of suitably detecting the position of a developing rack. It is intended to provide.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus moves a developing device and a main body side contact for electrical connection to a contact of a storage medium attached to the developing device. The position of the developing device is determined based on the detection result of the detection means, the detection means for detecting a signal from the contact of the storage medium, and the moving means to be brought into contact with the contact of the storage medium and the contact on the main body side Determination means.

  Preferably, there are a plurality of storage media, each of which is attached to the development rack, the detection means performs communication by detecting a signal from the storage medium, and the determination means is based on information stored in the storage medium. To detect the home position of the development rack.

  Preferably, the information includes developer color information.

  Preferably, the moving unit rotates the developing rack, and the determination unit performs determination based on a position where the contact of the storage medium and the main body side contact are connected and communication is possible.

  Preferably, the moving unit includes a motor, and the determining unit determines the position of the developing device based on a pulse for driving the motor.

  According to another aspect of the present invention, a method of controlling an image forming apparatus having a main body side contact for electrical connection to a contact point of a storage medium attached to a developer unit moves the developer unit. A moving step, a detection step for detecting a signal from the contact of the storage medium by bringing the contact of the storage medium and the contact on the main body side into contact, and a determination for determining the position of the developing device based on the detection result of the detection step Steps.

  According to still another aspect of the present invention, a control program for an image forming apparatus having a body-side contact for electrically connecting a contact of a storage medium attached to a developer moves the developer. A detecting step for detecting a signal from the contact of the storage medium by contacting the contact point of the storage medium and the contact on the main body side, and a position of the developing device based on a detection result of the detection step The determination step is executed by a computer.

  According to these inventions, it is possible to provide an image forming apparatus, a control method for the image forming apparatus, and a control program for the image forming apparatus that can suitably detect the position of the developing rack.

1 is a schematic cross-sectional view showing an overall configuration of a four-cycle digital full-color printer employing an intermediate transfer method in one embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a control unit included in the printer of FIG. 1. FIG. 4 is a schematic diagram illustrating a configuration of a component mounting surface side of a memory board provided in each developing unit. It is the schematic which shows the structure by the side of the contact of the memory substrate provided in each developing unit. FIG. 3 is a schematic diagram of a configuration of a contact on the image forming apparatus main body side. FIG. 3 is a schematic configuration diagram of a set of contacts including main contacts and scraper contacts provided on the image forming apparatus main body side. It is a figure for demonstrating the mechanism to which a scraper contact is moved up and down. 6 is a flowchart illustrating a developing rack driving process. It is a flowchart which shows the process coped with at the time of the communication failure by a contact. It is a figure which shows the detection method of the home position using a developing device mounting memory substrate. It is a figure for demonstrating the determination method of a home position. 6 is a flowchart illustrating home position determination processing executed by the image forming apparatus. 1 is a schematic cross-sectional view showing an overall configuration of a 4-cycle digital full-color printer employing an intermediate transfer system. It is a block diagram which shows the structure of the control part with which the printer of FIG. 13 is provided. FIG. 4 is a diagram showing a detection mechanism of a photosensor 17 for detecting a developing rack home position. FIG. 16 is a diagram showing an output waveform of a home position sensor 17 having the configuration of FIG. 15 and a driving pulse waveform of a motor for driving the developing rack.

  Hereinafter, a four-cycle image forming apparatus according to one embodiment of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing the overall configuration of a four-cycle digital full-color printer (hereinafter simply referred to as “printer”) employing an intermediate transfer method according to one embodiment of the present invention. The overall configuration of the printer and the configuration of its control unit will be described below.

  The basic configuration of the printer in FIG. 1 is the same as that shown in FIG. 13, and therefore, the description of the same parts will not be repeated. Hereinafter, features of the printer of FIG. 1 will be described.

  A contact having a scraper function (scraper contact) is mounted on the machine (image forming apparatus main body). When the developing rack is rotating forward, the scraper contact is retracted to a position where it does not function (a position where it cannot contact the contact of the memory board). When the developing rack is rotating in the reverse direction, the scraper contact moves to a functioning position (a position capable of contacting the contact of the memory board). In this way, by increasing the time during which the scraper contact does not contact the contact of the memory substrate, it is possible to reduce the wear of the contact during machine durability.

  The printer 1 is provided with a memory board connection contact unit 50. The main contacts 52 (which are composed of three main contacts 52a to 52c, details will be described later) are connected to the contacts of the memory boards 42Y to 42K mounted on each developing unit. Also, the memory board connection contact unit 50 includes a scraper contact 51 (which includes three contacts 51a to 51c for removing dirt such as dust and toner on the contacts of the memory boards 42Y to 42K. Will be described later).

  The printer 1 according to the present embodiment is not provided with the photo sensor 17 for detecting the developing rack home position shown in FIG.

  (2) Configuration of control unit 100

  FIG. 2 is a block diagram illustrating a configuration of a control unit included in the printer of FIG.

  The basic configuration of the control unit in FIG. 2 is the same as that shown in FIG. 14, and therefore, the description of the same parts will not be repeated. Hereinafter, features of the control unit in FIG. 2 will be described.

  The CPU 101 develops in order to activate the scraper contact 51 (contacts 51a to 51c) for removing dirt such as dust and toner on the contacts (contacts A to C) of the development unit mounting memory substrates 42Y to 42K. Control to reversely rotate the rack motor 91 is performed. The RAM 107 provides a work area for the CPU 101.

  The CPU 101 detects the home position of the developing rack by communicating with the memory boards 42Y to 42K mounted on the developing device without using the photo sensor. More specifically, the contacts A of the developing device mounted memory substrates 42 </ b> Y to 42 </ b> K are connected to the ground (GND) 109 in the control unit 100. The contact B is connected to DC5V108. The contact C that performs communication is connected to the GND 109 via the resistor R110. As a result, when these contacts A, B, and C are separated from the contacts (52a to 52c) of the memory board connection contact unit 50, the LOW level is input to the CPU 101.

  FIG. 3 is a schematic diagram showing the configuration of the component mounting surface side of the memory board provided in each developing unit.

  Memory boards 42Y to 42K are mounted on the color developing units 40Y to 40K. A perspective view of one component mounting surface side of the memory boards 42Y to 42K is shown in FIG. 3, and the microcomputers 43Y to 43K incorporating the nonvolatile memory are mounted.

  FIG. 4 is a schematic diagram showing the configuration of the contact side of the memory substrate provided in each developing unit.

  The perspective view of the contact side which is one back surface of the memory substrates 42Y to 42K is shown in FIG. 4, and the contact A, the contact B, and the contact C are formed on the contact side by gold plating. .

  The contact A is for GND connection, the contact B is for 5V power supply, and the contact C is a contact for bidirectional communication. The contacts A and B are contacts for supplying power to the nonvolatile memory built-in microcomputers 43Y to 43K.

  Through these contacts, the CPU 101 for controlling the main body communicates with the microcomputers 43Y to 43K with built-in nonvolatile memory, obtains information on each developing unit from the nonvolatile memory, and sends information such as the number of prints to the microcomputers 43Y to 43K with built-in nonvolatile memory Perform the write operation.

  FIG. 5 is a schematic diagram of the configuration of the contacts on the image forming apparatus main body side.

  The memory board connection contact unit 50 has the contact configuration shown in FIG. If dust in the apparatus or scattered toner adheres to the contacts (contacts A to C) of the development unit mounting memory substrates 42Y to 42K, contact failure may occur. Therefore, scraper contacts 51a to 51c for removing dirt are installed in the contact unit 50 for connecting the memory board. The scraper contacts 51a to 51c are arranged so that dirt on the substrate contacts A to C is scraped off when the scraper contacts 51a to 51c are physically in contact with the substrate contacts A to C. The scraper contacts 51a to 51c are installed in the vicinity of the main contacts 52a to 52c.

  When the scraper contacts 51a to 51c are always slid with the memory board contacts (contacts A to C) during the forward rotation of the developing rack 15 in the same manner as the main contacts, the memory board contacts (contacts A to C) are scraped. In some cases, dust or scattered toner enters the affected area, causing contact failure. In addition, the scraper contact itself is scraped to cause a problem that the scraper function cannot be maintained until the end of the machine life.

  Therefore, in the present embodiment, the operation of the scraper contact is performed at a timing other than the normal machine printing operation.

  Specifically, as shown in FIG. 5, the base 54 on which the scraper contacts 51 a to 51 c are installed is installed on a base 53 that is movable in the X direction. By moving the pedestal 53 in the X direction, the scraper contacts 51a to 51c can be moved up and down. The contacts 52 a to 52 c are installed on a fixed base 55. Each of the main contacts 52a to 52c is installed close to the scraper contacts 51a to 51c. These contacts are installed in the machine body as one unit 50.

  FIG. 6 is a schematic configuration diagram of a set of contacts including a main contact and a scraper contact provided on the image forming apparatus main body side.

  Here, the configuration of one scraper contact 51 of the scraper contacts 51a to 51c and one main contact 52 of the main contacts 52a to 52c is shown. The contact is biased by the coil springs 51e and 52e. Guides 51d and 52d for holding the coil springs 51e and 52e, the scraper contact 51 and the main contact 52 are provided.

  FIG. 7 is a view for explaining a mechanism for moving the scraper contact up and down.

  7 shows a configuration in which the vicinity of the developing rack 15 is viewed from the “G” direction in FIG.

  A developing rack driving gear (gear groove) is provided on the side of the developing rack 15. The developing rack drive gear meshes with a groove of the developing rack motor gear 90 attached to the shaft of the developing rack motor 91. The developing rack 15 can be rotated forward and backward as the developing rack motor 91 rotates.

  Developing units 40Y to 40K are mounted on the developing rack 15, and memory substrates 42Y to 42K are mounted on the developing units. The developing rack motor 91 is rotated by driving the developing rack motor 91, and the contacts (contacts A to C) of the memory boards 42Y to 42K are installed on the scraper contacts 51a to 51c on the pedestal 54 and the pedestal 55 (FIG. 5). The CPU 101 performs control so as to come to a position in contact with the main contacts 52a to 52c (FIG. 5).

  As described above, the base 54 on which the scraper contacts 51a to 51c are installed is installed on the base 53 that is movable in the X direction. By moving the pedestal 53 in the X direction, the scraper contacts 51a to 51c can be moved up and down.

  A protrusion 53 a is provided at the lower portion of the pedestal 53. A pedestal moving mechanism 56 for moving the pedestal 53 is provided below the pedestal 53. The pedestal moving mechanism 56 has a cylindrical shape, and rotates in the same direction as the rotation of the developing rack 15 via the pedestal moving mechanism drive gear. The pedestal moving mechanism 56 has grooves 56b and 56c provided in the circumferential rotation direction on the left and right sides, and further includes an oblique groove 56a that connects the grooves 56b and 56c.

  That is, the pedestal moving mechanism 56 is formed with a groove 56a for moving the pedestal 54 up and down and circumferential grooves 56b and 56c on both sides thereof. When the projection 53a provided on the pedestal 53 reaches the circumferential grooves 56b and 56c on both sides, the projection 53a is idle in the grooves 56b and 56c.

  The protrusion 53a of the pedestal 53 is engaged with the grooves 56a to 56c and slides and moves in the grooves 56a to 56c. In accordance with this, the pedestal 53 also moves in the left-right direction in the figure.

  When the developing rack 15 is rotated (forward rotation) during normal printing operation (the direction of rotation is indicated by an arrow on the right side of the developing rack 15 in the drawing), the pedestal moving mechanism 56 rotates in the same direction as the developing rack 15. As a result, the pedestal 53 moves sideways (to the left), and the pedestal 54 on which the scraper contacts 51a to 51c are installed is lowered. As a result, the scraper contacts 51a to 51c move to positions that do not contact the contacts (contacts A to C) of the memory boards 42Y to 42K.

  In order for the scraper contacts 51a to 51c to move to positions where they contact the contacts (contacts A to C) of the memory substrates 42Y to 42K, the developing rack motor 91 is reversely rotated and the developing rack 15 is reversely rotated at a predetermined timing. Is done. Due to the reverse rotation, the pedestal 53 moves sideways (to the right), and the pedestal 54 on which the scraper contacts 51a to 51c are installed rises.

  FIG. 8 is a flowchart showing a developing rack driving process.

  When the power switch of the machine body is turned on, the contents of the memory (RAM 107 in FIG. 2) of the machine body are checked (step S1). If the information stored in the memory substrate of each developing unit in the developing rack is not stored in the machine body (NO in step S2), the developing rack is rotated and its home position is detected (step S3). As a result, the rotational position of the developing rack can be accurately grasped.

  Next, the developing rack is stopped at the memory access position of the C color developer, and memory access is performed (step S4). Similarly, the K color developer memory access (step S5), the Y color developer memory access (step S6), and the M color developer memory access (step S7) are performed. As a result, information stored in each memory of the developing rack is stored in the machine body by communication.

  When determining whether information is stored in the memory in step S2, if it is stored (YES in step S2), it is further determined whether the main body cover has been opened (opened) (step S2). '). This is determined based on the output of the cover opening / closing sensor 99 (FIG. 2).

  If the cover is closed after being opened (YES in step S2 ′), the developing device may have been replaced, and the position of the developing rack is unknown, so the processing from step S3 to S7 is executed. Then, the memory of each developer is accessed.

  If the cover is not opened (NO in step S2 '), it is determined whether the number of prints is a predetermined number (step S3'). If the predetermined number has been reached (YES in step S3 ′), it is determined that the level of contact (contacts A to C) on the memory board is large with dust or toner, and the developing rack is removed as described above. The reverse rotation is performed for a predetermined time, and the scraper contact is moved to a position where it slides to the contact (contacts A to C) of the memory substrate of each developing device (step S4 ′). Reverse rotation removes contact dust and toner stains. The degree of contamination in the machine is predicted from the number of printed sheets, and cleaning is performed according to the prediction. The prediction may be performed not by the number of printed sheets but by the number of rotations of the developing rack.

  If the predetermined number of prints has not been reached (NO in step S3 '), the process is terminated without reverse rotation of the developing rack.

  As described above, the scraper contacts are operated (functioned) only when the developing rack 15 rotates in the reverse direction, thereby suppressing the wear of the contacts (contacts A to C) on the memory substrate and the wear of the scraper contacts. Can do. Further, it is possible to always stably remove the dirt on the contacts (contacts A to C) on the memory substrate, prevent the occurrence of communication failure with the memory, and enable stable operation of the machine.

  FIG. 9 is a flowchart showing a process for dealing with a communication failure caused by a contact.

  Referring to the drawing, in step S11, it is determined whether or not a communication failure (failure or communication error) between the memory board contacts (contacts A to C) and the memory board connection contact unit 50 has occurred. If YES, in step S12, it is determined that the level of the contacts (contacts A to C) on the memory substrate is large with dust or toner, and as described above, the developing rack is reversely rotated for a predetermined time, and the scraper contacts Is moved to a position where it slides to the contact point (contact point A to C) of the memory substrate of each developing device, and then the contact point A to C is cleaned. Thereby, dust and toner stains on the contacts are removed.

  [Development rack home position detection process]

  FIG. 10 is a diagram illustrating a home position detection method using a developing device mounted memory substrate.

  The moving direction of the memory boards 42Y to 42K mounted with the developing device (the rotating direction of the developing rack 15) is the Y direction in the figure. The positions where the contacts (52a to 52c) of the memory board connection contact unit 50 are connected to the contacts (contacts A to C) of the memory board are indicated by “communication area” in the drawing. At time T1, which is the start of the “communicable area”, the output of the contact C that performs communication output of the memory board becomes High level. Further, when the developing rack 15 further rotates and the time (T2) when the contacts (52a to 52c) of the memory board connection contact unit 50 are separated from the memory board contacts (contacts A to C), the output of the contact C becomes low level.

  This is because the nonvolatile memory built-in microcomputers 43Y to 43K of the developing device mounted memory substrate are pre-programmed so that the High level is sent as a communication output immediately after the reset is released.

  “Development rack motor drive timing” in FIG. 10 indicates a state in which the development rack 15 is rotating while the motor drive pulse is sent to the development rack motor 91 while it is High.

  FIG. 11 is a diagram for explaining a home position determination method.

  The main body control CPU 101 detects a period in which the communication output at the contact C of the developing device mounting memory substrate is at a high level. By correlating the output of the developing rack motor drive pulse with the above period, the center position of the High level period is determined as the home position.

  As shown in FIG. 11, the number of developing rack motor drive pulses in the high level period of the communication output of the contact C is nine. For this reason, when the communication output of the contact C is switched from the high level to the low level, the home position is determined to have returned five pulses, which is half of the high level period.

  FIG. 12 is a flowchart illustrating home position determination processing executed by the image forming apparatus.

  When the power of the printer main body is turned on or the cover of the main body is opened and closed, the developing rack 15 starts to rotate forward. At this time, counting of drive pulses of the developing rack motor is started (S101).

  Thereafter, it is determined whether or not the communication output of the developing device mounted memory substrate is at a high level. If it is not High level, it is determined that the contacts (contacts A to C) of the memory board are not connected to the contacts (52a to 52c) of the contact unit 50 for connecting the memory board (NO in S102), and the developing rack motor is turned on. To drive.

  If the level is high (YES in S102), it is determined that the contacts (contacts A to C) of the memory board are connected to the contacts (52a to 52c) of the contact unit 50 for connecting the memory board, and the developing rack motor is temporarily stopped. (S103). At this time, the main body control CPU 101 starts communication with the memory board.

  Specifically, the main body control CPU 101 obtains color information from the memory board. If the memory board with which the communication has been performed is not for the black developing device (NO in S104), the developing rack motor is driven for a predetermined number of steps (S105 '). The predetermined number of steps indicates the number of developing rack motor driving pulses for rotating the developing rack by about 90 degrees.

  In this embodiment, the developing rack motor is a stepping motor and is driven by two-phase excitation. The machine is configured such that the drive pulse is 2000 pulses and the developing rack rotates once (360 degrees).

  That is, if the motor is driven with 500 pulses, the rack rotates 90 degrees, and the contacts (52a to 52c) of the memory substrate connection contact unit 50 can reach the memory substrate of the next developing device. In the present embodiment, driving is performed with 667 pulses for 120-degree rotation so as to reach the next developing unit sufficiently. As described above, in step S102, it is determined whether the communication output of the memory is high level. If YES, the processing from step S103 is performed.

  If it is determined in step S104 that the developing device is a black developer, the developing rack motor is further rotated (S105), and the communicable area described with reference to FIGS. 10 and 11 is detected. At the same time, the motor drive pulses are counted.

  During the rotation, it is determined whether the communication output of the memory board is at a high level (S106). If it is High level, the rotation of Step S105 is continued.

  When the communication output of the memory board becomes low level (NO in S106), ½ of the number of developing rack motor driving pulses during the period when the communication output of the memory board is high level is calculated. The position of the development rack whose rotation has been returned by the calculated number of drive pulses is determined as the home position (S107).

  With the above processing, the home position (the black position of the developing rack) can be determined using the developing device mounting memory substrate. As a result, the conventional photo sensor can be eliminated.

  [Effects of the embodiment]

  As described above, the developing unit is mounted on the developing rack. Communication is performed between the memory mounted on the developing unit and the machine body control CPU. By rotating the developing rack and connecting the contacts of the memory board and the contacts on the machine body side, the machine body control CPU and the memory board can communicate with each other. At this time, the developing rack stops. The home position is calculated based on the stop position.

  That is, the home position is calculated by detecting a communicable position with the memory of the memory board mounted on each color developing unit instead of the home position sensor of the developing rack. Further, the home position is determined based on the information stored in the memory. In particular, in the embodiment, the home position is determined based on the color information of the developing unit.

  As described above, since the home position can be determined based on the communication contents between the memory mounted on the developing unit and the machine body control CPU, the photo sensor for detecting the developing rack home position can be eliminated. .

  Further, according to the configuration in the above-described embodiment, the scraper contact functions only when it is rotated in the reverse direction with respect to the rotary rotation direction at the time of normal image formation in order to reduce contact wear during machine durability. I am doing so.

  That is, if the contact having the scraper function is slid with the memory substrate contact on the developing device when the developing rack is driven to rotate in the normal direction, the contact wear increases. As in this embodiment, by causing the scraper contact to function only when the developing rack is reversely rotated, contact wear can be reduced, and stable contact performance can be maintained.

  More specifically, the degree of contamination in the machine is predicted by the number of rotations (or the number of printed sheets) of the developing rack, and the scraper contact is made to function when the predetermined number of rotations (or the number of printed sheets) is reached to remove the dirt. . As a result, it is possible to prevent the occurrence of communication failure with the development unit mounted memory and to enable stable operation of the machine. Furthermore, when a communication error occurs, the stable contact performance can be maintained at any time by immediately operating the scraper function.

  [Others]

  In addition, as a scraper contact, the thing of a conductor may be used and it may be made to conduct | electrically_connect with the corresponding main contact, and the thing of an insulator may be used.

  In the above embodiment, the scraper contact is moved relative to the position of the developing rack. Conversely, the developing rack may be moved relative to the position of the scraper contact. You may move both.

  Note that the processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program is executed by a computer such as a CPU. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Printer 2 Photosensitive drum 4 Developing apparatus 6 Intermediate transfer belt 7 Secondary transfer part 8 Cleaner part 11 Exposure part 15 Developing rack 40Y-40K Each color developing unit 41Y-41K Developing roller 42Y-42K Memory board 50 Memory board connection contact unit (connector)
51, 51a to 51c Scraper contact 52, 52a to 52c Contact (main contact)
71 Secondary Transfer Roller 73 Transfer Roller Solenoid 81 Cleaning Blade 84 Cleaner Solenoid 100 Control Unit 101 CPU
DESCRIPTION OF SYMBOLS 102 Interface part 103 Image processing part 104 Image memory 105 LD drive part AC Contact point of memory boards 42Y-42K

Claims (7)

A main body side contact for electrical connection to a contact point of a storage medium attached to the developing device;
Moving means for moving the developing device;
Detecting means for detecting a signal from the contact of the storage medium by bringing the contact of the storage medium into contact with the contact on the main body side;
An image forming apparatus comprising: a determination unit that determines a position of the developing device based on a detection result of the detection unit. There are a plurality of storage media, each of which is attached to a development rack,
The detection means performs communication by detecting a signal from the storage medium,
The image forming apparatus according to claim 1, wherein the determination unit detects a home position of the developing rack based on information stored in the storage medium.   The image forming apparatus according to claim 2, wherein the information includes color information of the developing device. The moving means rotates the developing rack,
The image forming apparatus according to claim 2, wherein the determination unit performs determination based on a position where the contact of the storage medium and the contact on the main body side are connected and communication is possible. The moving means includes a motor,
The image forming apparatus according to claim 1, wherein the determination unit determines a position of the developing device based on a pulse for driving the motor. A control method of an image forming apparatus provided with a main body side contact for electrical connection to a contact point of a storage medium attached to a developing device,
A moving step for moving the developing unit;
A detection step of detecting a signal from the contact of the storage medium by bringing the contact of the storage medium into contact with the main body side contact;
And a determination step of determining a position of the developing device based on a detection result of the detection step. A control program for an image forming apparatus having a main body side contact for electrical connection to a contact point of a storage medium attached to a developing device,
A moving step for moving the developing unit;
A detection step of detecting a signal from the contact of the storage medium by bringing the contact of the storage medium into contact with the main body side contact;
A control program for an image forming apparatus, which causes a computer to execute a determination step of determining a position of the developing device based on a detection result of the detection step.

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